Monophonic texture was the dominant musical texture from 200 CE to 1300 CE during the early Christian era. It involves a single melodic line with one part sung or played. The best example is plainchant or plain song, which were ritual melodies used in early Christian churches that rose and fell in pitch with the words. In the 6th century, Pope Gregory I collected all existing chants and arranged them for use in Roman churches. Neums were an early notation system using curved lines to indicate pitch, while the staff introduced lines to notate pitch in the 11th-12th centuries.